Just got to thinking about some of the problems that may have to be addressed if & when we ever try to visit Titan in person.

The first thing that comes to mind is what might happen if some Titanian air gets inside an oxygen-rich manned spacecraft, say from minor airlock residue. I imagine that the explosive potential of some of the trace gasses is pretty high, and there's probably also a significant risk of poisonous compounds as well. So, here are some tenative requirements:

In reference to your item #4... here's something from 1960. There was a TV show that tried to "accurately" portray man going into space and to the moon. Here's the lead actor of that series showing he has the right stuff as a macho astronaut... Well... it was 1960, after all. Guess no "lighting up" on Titan. ('Course there always is niccotine gum)

You definitely want a very efficient air filtering system. Obvious flammability aside if enough Titan air got into an enclosed environment, you also have to be concerned about the amount of benzene that a settler would come into contact with: http://www.scorecard.org/chemical-profiles..._id=71%2d43%2d2

I find it compelling that you could go around on Titan, pick up "rocks" you find interesting and when you get back to the ship, all those rocks just melt away under earthly temperatures. There's something about the fact that entire mountains, everything you see there would just melt if you held it in your hands long enough. Provided you had big enough hands...

An ocean world in out mindset, yet rock solid... Not to mention even more extreme cases like Triton!

I find it compelling that you could go around on Titan, pick up "rocks" you find interesting and when you get back to the ship, all those rocks just melt away under earthly temperatures. There's something about the fact that entire mountains, everything you see there would just melt if you held it in your hands long enough. Provided you had big enough hands...

An ocean world in out mindset, yet rock solid... Not to mention even more extreme cases like Triton!

If the surface is not very rocky (rocks or water ice rocks), perhaps cross-country skis might be a viable transport mechanism. Adjust heat flow from suit radiators into the skis to avoid freezing in place.

On worlds further out, e.g., more distant TNO's, where the surface is frozen gas, allowing heat radiators in uncontrolled contact with the surface might cause the gas to boil off violently.

I was thinking that you could get away with basically a 'warm suit' with breathing gear ( i.e. the Baxter suggestion in 'Voyage' )

HOWEVER.....

The only way to not contaminate from outside to inside the module via the airlock would be to evacuate it to as near a vacuum as you can at each cycle..

i.e. people put on suits, get in. 'habitable' air then pumped out into a pressure vessel so the airlock is at as near a vacuum as can be made.

THEN - you repressurise with 'titanian' air up to titanian pressue.

On the way back in - shut the door, pump out to a vacuum dumping it to the atmosphere outside, then represurise with the air evacuated before the EVA began...that would minimise the cross contamination in the meantime

BUT

It then means you have to have an EVA suit that can manage a near vacuum so it's going to look more like a modern EVA suit rather than something more minimal that one might immediately assume would be enough for Titan.

1.6+ bar and mostly nitrogen to boot. If the lander & EVA suits were pressurized at that level, it sounds like the crew could get a BAD case of the bends when they return to the mother ship unless they decompress...better add a zero-gee decompression chamber to the shopping list!

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A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.

A vacuum capable airlock might be rather heavy to drag all the way to Titan, maybe the airlock could be a conformal bag, and the pressure difference could squeeze the atmosphere back outside.

Residual gases would still be present but could be dealt with something not too dissimilar to the lithium hydroxide packs, just use a different chemical for the hydrocarbon smog absortion you want.

I suspect flammability won't be much of a concern due to dilution below the ignition concentration (atmosphere is mostly N2 in any regard), but I suspect the smell of the Titanian atmosphere will be hideous.

Why would it be hideous? Surely not due to methane itself as the gas is odorless, contrary to popular thinking. As for smog particles, their concentration in the air is probably lower than in a smoggy city back here.

From the Titan chapter in The New Solar System, I see we might expect besides the nitrogen, methane and argon, to find methyl radicals (CH3), ethane, acetylene, ethylene, polyacetylene, cyanide, and various breakdown products of several of them. I suspect Cassini will be casting a far better understanding of the atmospheric constituents.

It may be possible there is still some ammonia extant there too, perhaps most of the nitrogen in the atmosphere is from dissassociated ammonia after all, and it might be clatharated with the water ice.

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